The invention relates to shoulder harness and lap belt restraints of the type having a pair of shoulder straps anchored behind the head and extending down over the occupant's shoulders to lower, side anchor points adjacent opposite sides of the seat pan, and having a lap belt extending from one side anchor to the other across the occupant's lap. More particularly, the invention relates to restraints of the foregoing type in which the shoulder straps and lap belt are integrated by using a common length or lengths of webbing for both the lap belt and shoulder straps.
While existing restraint system for automobile, aircraft and other vehicles have undoubted value in increasing of the safety of travel, recent studies have been undertaken to make improvements, if possible, to available restraint equipment. One such study, conducted with respect to restraint systems used by flight attendants on commercial carriers, has indicated that a combined shoulder harness and lap belt restraint characterized by five or six anchor points is quite effective, in minimizing the potential for severe bodily injury, when compared with a number of other commonly used restraints.
The five/six point anchor systems are characterized by shoulder straps anchored behind the occupant's head and extending over the occupant's shoulders and down along the upper torso to lower side anchor points adjacent the opposite sides of the seat pan, and by a lap belt extending between the same or adjacent side anchor points across the occupant's lap. In the five point system, the ends of the lap belt and the lower ends of the shoulder strap constitute four separate anchor points and the upper end of the shoulder straps are merged in an inverted Y and are anchored to one point for a total of five anchor locations. In the six anchor point system, the shoulder straps remain separated and are individually attached to two behind-the-head anchors for a total of six anchor locations. A combined shoulder and lap restraint having this basic configuration has been shown to be especially effective in restraining the body under deceleration conditions in such a way as to minimize the tendency of the body to submarine, i.e., slippage of the pelvis region under the lap belt, and in decreasing the potential for lumbar compression, i.e., axial compression of the spine. The five/six point anchor systems have been compared in the foregoing respects with such popular restraint systems as the bandolier configuration formed by a lap belt and a single shoulder strap crossing the upper torso; a three point restraint formed by a lap belt and two shoulder straps that extend from a single behind-the-head anchor and first diverge to pass on opposite sides of the occupant's head and then extend downwardly in a convergent fashion to a center buckle at the mid-point of the lap belt; and a four point restraint that is similar to the above three point system except that the upper ends of the shoulder straps are independently attached to separate anchors located above and behind the occupant's shoulders.
The five/six point anchor systems are also believed to be more reliable than a related restraint configuration that is superficially similar but has only three (or four) anchor points. The latter system is characterized by shoulder straps of continuous lengths of webbing which are slidably looped through non-friction slip fittings on the side anchors and extended in a continuous fashion therefrom inwardly as a lap belt to a lap buckle where the ends of the webbing lengths are releasably connected by the buckle. Because of the slip fittings at the side anchors, the lower ends of the shoulder straps and the opposite ends of the lap belt are not separately anchored and hence this configuration is not a true five or six point anchor system. Free, unrestrained slippage of the webbing at the side anchors allows the lap belt to lengthen under certain force conditions which in turn permits the pelvic region of the body to submarine under the lap belt. On the other hand, excessive tension on the webbing in the region of the shoulder straps is transmitted into tightening of the lap belt, which consequently may become excessively tight and cause injury to the lower stomach or pelvic region.
While it is thus seen that the five/six point anchor systems have certain characteristics which are preferred over other commonly used restraints, previously known implementations of the five and six point restraints have a serious drawback because of their inability to provide quick, tangle-free donning and rapid releases and egress, especially under emergency conditions. Other restraints such as the bandolier and three and four point systems have configurations which lend themselves to the use of a single point release for quick donning and escape, but the five/six point anchor systems are not so readily adapted to a single point release, and heretofore have generally required at least two release locations which militates against rapid release and egress. One implementation of the five/six point restraint systems does use a single point release, located at one of the side anchors for jointly connecting the ends of an adjacent shoulder strap and lap belt to the side anchor. A strap length adjuster on the opposite and nonreleasing shoulder strap is used to snug up the shoulder harness. This particular implementation of the five and six point system, however, has proved difficult to use and has not been widely adopted.
Accordingly, it is an object of the invention to provide an integrated shoulder harness and lap belt restraint of the five/six anchor point type that is relatively easy to don and snug up, and yet can be quickly released and shed for emergency egress. A related object is to provide such a restraint apparatus wherein its operation and use are self-evident and thus does not require independent instruction or explanation in the proper usage.
Another object is to provide an integrated restraint apparatus having the above desirable trains in a configuration that can be economically mass manufactured so as to favor comparably in cost to other combined shoulder harness and lap belt restraints that may not have the effectiveness, safety benefits and rapid release feature afforded by the five/six point anchor restraints.
Still another object of the invention is to provide a five/six point restraint apparatus that meets the foregoing objectives and furthermore is suitable for retrofitting seat installations already equipped with seat belts and the associated seat side anchors.